from machine import Pin, PWM
from time import sleep

buzzer = PWM(Pin(32,Pin.OUT))
       
while (True):
    buzzer.duty(50) #on buzzer

    buzzer.freq(300)
    sleep (0.2)
    buzzer.freq(350)
    sleep (0.2)
    buzzer.freq(400)
    sleep (0.2)
    
    buzzer.duty(0) #off buzzer
    sleep (2)